Circulating overshot with segmental grapple member



Oct. 11, 1960 J. B. HORN, JR 2,955,868

CIRCULATING OVERSHOT WITH SEGMENTAL GRAPPLE MEMBER Filed Sept. 29, 1958 Lu-i L/OCAJON E. f/orn,J/'.

INVENTOR.

ATTORNEY CIRCULATING OVERSHOT WITH SEGMENTAL GRAPPLE MEMBER Jackson B. Horn, Jr., 2429 Crockett St, Houston, Tex.

Filed Sept. 29, 1958, Ser. No. 764,035

4 Claims. (Cl. 294-402) This invention relates to a grappling tool for use in removing stuck objects, such as pipe and the like from wells.

The invention finds particular application in connection with grappling tools of the circulating overshot type in which the tool is lowered into a well connected to a tubular operating string to position the tool over the upper end of a stuck pipe in the well to grippingly engage the stuck pipe and connect the same to the string while permitting the circulation of fluid through the string to release the stuck pipe.

Grappling tools of this character, as heretofore commonly constructed include an outer tubular part or bowl adapted to be connected at its upper end to the lower end of the operating string for lowering into the well to position the bowl about the upper end of the stuck pipe and having an internal annular or spiralled downwardly converging seat. An expansible, internally Wickered, grapple member or inner part of tubular shape is movably positioned in the bowl and has an external annular or spiralled, downwardly tapering face positioned for engagement with the internal seat of the bowl. In use, the tool is lowered over the stuck pipe to extend the pipe through the grapple member to expand the member into gripping engagement with the exterior of the pipe so that upon the exertion of an upward pull on the string the external face of the grapple member will engage the internal seat of the bowl to contract the member into tight gripping engagement with the pipe.

Heretofore, the grapple members of tools of this kind have customarily been formed in one piece with a longitudinal slot extending from end to end therethrough, and at times with additional longitudinal slots extending partly through the length of the member, to permit the member to be expanded and contracted.

Grapple members of this type, when made in one piece, must be formed of steel of specially selected quality, since the members must be of sufficient hardness to permit the internal teeth of the members to penetrate the stuck pipe, while at the same time they must have sufficient resiliency to allow the members to be expanded and contracted without breaking. Moreover, when made in one piece, any defect in the grapple member makes it necessary to discard the entire member.

The present invention has for an important object the provision of a grappling tool of the type above described embodying a grapple member which is formed in segmental parts of relatively, hard, non-resilient material such as steel, including flexible, resilient means for holding the parts assembled to form a tubular expansible and contractible body.

Another object of the invention is to provide a grappling tool of the kind mentioned having a multi-part grapple member made up of parts which may be economically manufactured and which are easily assembled and disassembled for purposes of maintenance and repair.

A further object of the invention is the provision in grappling equipment of the type referred to of a grapple Patented Oct. 11, l90

member formed in segmental sections of relatively hard inflexible and non-resilient material, such as steel, assemblcd and connected together by a tension ring element formed of relatively flexible, resilient and nonbrittle material, such as spring steel, to form an expansible tubular body.

A still further object of the invention is to provide a grappling tool of the kind referred to having multipart tubular expansible grapple member of simple design and rugged construction capable of withstanding the extreme conditions of stress and hard usage to which objects of this character are customarily subjected.

The above and other important objects and advantages of the invention will best be understood from the following detailed description, constituting a specification of the same, when considered in conjunction with the annexed drawings, wherein:

Figure 1 is a vertical central, crosssectional view of the grappling tool of the invention showing the tubular inner part of grapple member in its inactive or unexpanded condition preparatory to engagement of the tool with the stuck pipe;

Figure 2 is a side elevational View, on an enlarged scale, of the grapple member of the invention removed from the tool; and

Figure 3 is a cross-sectional view, taken along the line 3-3 of Figure 2, looking in the direction indicated. by the arrows.

Referring now to the drawings in greater detail the grappling tool of the invention comprises an outer tubular part or bowl in having an internally threaded upper end portion or box 12 for the connection thereto of the externally threaded lower end 14 of the lowermost section 16 of a tubular operating string of pipe of the usual kind whereby the tool may be lowered into a well and operated therein to connect the tool to the stuck pipe. At its lower end the bowl it is provided with an externally reduced portion 18, which is externally threaded for connection to the upper, internally threaded portion 2% of a tubular guide 22 whose lower end is formed with an internally beveled end face 24 positioned to be engaged by the upper end of the stuck pipe to guide the same into the bowl.

The guide 22, has an internal annular recess 26 therein within which a seal forming element 28 is positioned to form a seal between the exterior of the stuck pipe and the guide when the pipe is extended into the bowl.

The guide 22 has an upper end counterbore whose bottom wall forms an internal, annular, upwardly facing, beveled shoulder 3t and the bowl 310 has a lower end counter-bore 32 forming an annular, downwardly facing, internal shoulder 34.

A tubular grapple control element as is positioned in the bowl in engagement at its upper end with the shoulder 34 and whose lower end is formed with an internally beveled end face 38 positioned in contact with the shoulder 3i whereby the control element is retained in and held against rotation relative to the bowl. The control element has an upwardly extending projection 49 at its upper end fora purpose to be explained hereinafter.

The bowl 1% in the present illustration is formed with an internal, spiralled, downwardly converging seat 42, and above this seat is provided with a portion forming an internal downwardly facing spiralled shoulder 44.

An expantible, multipart, generally tubular shaped grapple member 46, shown in detail in Figures 2 and 3, is positioned in the bowl F10. The grapple member is made up of a number of segmental sections 45, four such sections being shown in the present illustration, which are internally toothed or wickered, as seen in 47, and formed with external downwardlytapering faces 48 r t V 3 terminating in external upwardly facing shoulders 50. The external faces 48 are positioned to be in spiralled arrangement about the exterior of the tubular body or :grapple member 46 to conform to and ride against the internal spiralled seat 42 of the bowls and the shoulders .50 are similarly arranged to engage the spiralled shoulder .44 of the bowl. V

a Each of the segmental elements 45 has an external, peripherally extending groove 52 near its lower end into which a flexible, resilient, annular, split band or ring 54 extends when the segments are assembled, this band serving as a connector member for holding the segments .inperipherally spaced arrangement toform the tubular expansible body of the grapple member and being provided for that purpose with suitably located openings 56' through which screws 58 are extended which are threadably connected to the segments.

' When in assembled condition and connected together by the band 54 the'segments 45 are spaced apart periph-- erally to form slots 60 between the segments extending from end to end of the body of-the grapple member.

seen at 62 in Figure 1 to provide a recess in the lower end of the grapple member when the segments are assembled and the bowl has an internal, longitudinal ,key-way' 63 (shown in dotted lines in Figure 3) into which recess and key-way the projection 40 0f the grapple control 36 is extended to hold the grapple member against rotaton relative to the bowl during the operation of the overshot; f

, In making the segmental bodyof the grapple member, the body may be made in one-piece and afterward cut into segments, and in the eventthat some of the segments thus made should be defective, others may be substituted therefor in assembling the member. Broken, damaged or worn segments may also be easily removed and replaced. Also, by constructing the grapple member as above described the character or quality of the materials from whichthe segments and band are made may be selected in any manner desired, so'that the segments may be madeas strong and hard as required and the band may be made flexible and resilient to permit expansion and contraction of the grapple member without danger ofbreakagetdue to embrittlement. V i

Grapple members made in this way also possess th advantage that they may be i internally wickered or threaded, as shown at 47, throughout this entire length,

Cit being unnecessary to leave any unthreaded portions at the ends of such members to form tension ring portions,

7 such as those provided in grapple members as commonly constructed heretofore. By so internally threading the grapple member throughout its entire length, more 7 effective gripping of the lost object is obtained upon contraction of the grapple member in engagement with the object. 1 t f In the operation of the overshot of the invention, constructed and arranged as described above, the grapple member 46 'will be at its lowermost position in the bowl and inunexpanded condition during the lowering of the tool on the operation string, as shown in Figure 1; When the tool is engaged with the stuck pipe in the well,the upper end of the pipe will be guided into the lower end of the bowl through the guide 22 and will move the grapple member upwardly until the upwardly facing shoulders ,member to expand the grapple member to cause the i11- ternal teeth of the segments to grippingly engage the exterior of the pipe, with the stuck pipe or fish thus positioned in the tool an upward pull may be exerted on the operating string to move the bowl upwardly while the grapple member is held against such upward movement by the stuck pipe to cause-the external faces 48 to engage the internal seat '42, whereupon the segments will be moved inwardly to contract the grapple member into tight gripping engagement with the pipe. In this condition of the equipment the seal forming element 26 will be in sealing contact with the exterior of thestuck pipe so that circulation-of fluid may take place through the operating string and pipe to help free the pipe from the wall, and the operating string can be manipulated to recover the pipe from the well.

Should it be found impossible to release the stuck pipewhen it has been thusconnected tothe operating string, the string may be related tothread the grapple member 0E of the pipe to disconnect the string from the p1pe.

It will thus be seen that the invention provides a circulating overshot which is of simple design and rugged construction having a grapple member which is easily expansible and contractible and in whichthe parts may be readily replaced when worn or broken. f

The invention is being disclosed herein in connection with a certain specific embodiment of the same, but it i will be understood that this is intended by way of example only, and that various changes can be made in the structure and arrangement of the parts within the spirit of the invention and the scope of the appended claims; V I

Having thus clearly shown and described the invention, what is claimed as new and desired tovs'ecure by Letters Patent is: i a

hl. On overshot adapted to telescope over an object stuck in'awell bore,,comprising atubular bowl having 'a' downwardly converging'inside seat, a plurality of segmentally shaped grapple elements movably disposed in the bowl each having an external downwardly converging face to conform to' and rest on said seat,'radially expansible means disposed in" radially inwardly spaced relation to said faces and connecting the elements together in peripherally spaced relationto hold the elements against relative longitudinal movementand Qto yieldingly hold the elementstagainst inward radial movement relative to the bowl.

2. An overshot, adapted .to telescope "over an object stuck in a Well bore, comprising a tubular bowl having a downwardly converging inside seat, a plurality. of, segmentally shaped grappletele ments movably disposed in the bowl each having'an externalfdownwardlyi convergmg face to conform to the contour of and rest on said seat and an external peripherally extending groove, an annular expansible connector member extending peripherally about the exterior of the elements in said grooves in radially inwardly spaced relationto said faces and connected to, the elements to hold the elements in peripherally spaced. relation for longitudinal movement in unison and to yieldingly urge the elements radially outwardly relative to the bowl. 7 1 v i 3. An overshot; adapted to telescope overan object stuck in a well bore, comprising a tubular bowl'having a downwardly converging inside-seat and an annular insiderecess' beneath the seat, said bowlalso having an inside longitudinal keyway; a pluralityof Segmentally shaped grapple elementsmovably disposed in the bowl each" having an external I downwardly; converging face to conformto' the contour of and rest on 'saidiseat, means disposedin radially inwardly spaced relation to said faces and connecting said elements together fto tform a, unitary expansible body of tubular? shape havingfa longitudinal side slot, and a controlling member in said recess. in-

eluding a key seated in said keyway and extended into said slot.

4. An overshot adapted to telescope over an object struck in a Well bore, comprising a tubular bowl having an inside, spiraled, downwardly converging seat, a plurality of segmentally shaped grapple elements movably disposed in the bowl each having an external downwardly converging face to conform to the contour of and rest on said seat and an external peripherally extending groove whose side Walls intersect said face, an annular expansible connector member extending peripherally about the elements in the grooves radially inwardly of said faces and connecting said elements together for longitudinal movement in unison and to yieldingly urge the elements radially outwardly relative to the bowl.

References Cited in the file of this patent UNITED STATES PATENTS North Mar. 11, 1902 Stephens Jan. 30, 1923 Horton June 17, 1924 Gore Oct. 6, 1925 Hunt Nov. 10, 1925 Nielsen Aug. 30, 1927 Fisher Aug. 24, 1937 Hinderliter Jan. 18, 1938 LeBus Mar. 10, 1942 Osmun Dec, 13, 1949 

